The phrase "let down flaps" refers to the process of extending the movable panels on the wings of an aircraft to increase drag and lift. The word "let" is spelled with the /lɛt/ sound, which is pronounced with the tongue lightly touching the back of the top teeth. "Down" is pronounced with the /daʊn/ sound, with the back of the tongue lifted towards the soft palate. "Flaps" is pronounced with the /flæps/ sound, with the lips coming together to produce the /f/ sound, followed by the tongue touching the back of the top teeth to produce the /l/ sound, and then transitioning into the /æ/ sound produced in the mouth's front area.
Let down flaps, also known as wing flaps or simply flaps, is a term used in aviation to refer to movable sections of the trailing edge of an aircraft wing. These devices are designed to increase the lift generated by the wing at slower speeds, such as during takeoff or landing.
When the let down flaps are deployed, they effectively change the shape of the wing, resulting in increased camber and surface area. This alteration creates more lift by increasing the pressure difference between the upper and lower surfaces of the wing. By increasing the lift, the aircraft's stall speed is reduced, allowing for slower and safer takeoffs and landings.
The let down flaps can be of various types, including plain flaps, split flaps, slotted flaps, or Fowler flaps. Each type has its own specific configuration and deployment mechanism, but they all serve the same purpose of modifying the wing's performance and aerodynamic characteristics.
In addition to enhancing lift, let down flaps also increase drag, which assists in slowing down the aircraft during descent and approach to landing. The drag helps reduce the aircraft's speed and steepen its descent angle, allowing for a smoother and more controlled touch-down.
Overall, let down flaps are crucial aerodynamic devices that improve an aircraft's performance and safety during takeoff and landing phases of flight by increasing lift and drag, respectively.